Here, a molded body surface should be taken to mean any area or surface on a substrate of any design or on a molded body of any shape and dimensions.
For reasons connected with weight, substrates and/or molded bodies are often formed from plastics. Correspondingly designed substrates and/or molded bodies can therefore be optimized in terms of weight but can also have a reduced stability. To increase stability, the substrates and/or molded bodies can be provided with a reinforcing structure. This reinforcing structure can be formed from fiber-reinforced thermosetting or thermoplastic materials, for example.
One example of a molded body or substrate is an inner container of a pressurized container. The pressurized inner container can be formed from a thermoplastic material, for example, or it can at least include a thermoplastic material. Pressurized containers are used to store pressurized gases and/or pressurized liquids. Thus, pressurized containers are already being used in motor vehicles operated on natural gas. Pressurized containers which are filled with pressurized hydrogen are furthermore known for motor vehicles. The hydrogen can be burned with oxygen in an internal combustion engine or can react with oxygen in a fuel cell to form water, wherein the electric energy obtained is fed to an accumulator or to an electric motor.
Corresponding pressurized containers must withstand high loads. Pressurized containers for natural gas are charged with a pressure of up to 250 bar, for example. Pressurized containers for hydrogen are charged with a pressure of up to 700 bar. The pressurized inner containers which form the interior of a pressurized container of this kind and are formed from a thermoplastic material, for example, must therefore be provided with a supporting structure which allows reinforcement of the pressurized inner container, ensuring that the pressurized container can withstand pressure loads of up to 700 bar.
The prior art has disclosed the practice of applying a supporting structure composed of thermoplastic material to a molded body, wherein the thermoplastic material is fiber-reinforced, in particular reinforced with carbon fibers. In this case, a reliable and stable connection between the molded body and the supporting structure is necessary.
Thus, U.S. Pat. No. 6,451,152 describes a method for producing plastic articles from a plastic strip. For this purpose, opposite surfaces of a plastic strip and of a substrate are subjected to laser light emitted by a laser diode array and are heated. After the respective heating surfaces have been heated, the plastic strip is positioned on the surface of the substrate and pressed onto the substrate by means of a contact pressure unit, with the result that the plastic strip adheres to the substrate. According to the description of U.S. Pat. No. 6,451,152, the surfaces of the plastic strip and of the substrate can be irradiated with appropriate intensities in a locally resolved way, with the result that, in the case of application of the plastic strip to the substrate over a curve, for example, the region of the plastic strip on the inside of the curve is heated more strongly to ensure that the plastic strip can be deposited on the substrate and joined to the latter more effectively in curved form.
U.S. Pat. No. 6,451,152 describes the use of a laser diode array which comprises a multiplicity of laser diodes, which are designed as “edge emitters”. Edge-emitter laser diodes have a high beam divergence, this having the effect that the diameter of a light cone emitted by the laser diode array increases quickly with distance from the laser diode array. To enable the intensities required to heat the heating surfaces of the plastic strip and of the substrate to be achieved, imaging optics designed as collimation optics are positioned between the laser diode array and the surfaces to be irradiated. Without the use of imaging optics arranged optically downstream of the laser diode array, it would consequently be impossible to use a large proportion of the laser power to heat the plastic strip and/or the molded body.
However, the use of imaging optics has various disadvantages. Corresponding imaging optics are very costly, increasing the costs of the overall device. Moreover, imaging optics get dirty during the use of the device, making it necessary to clean the imaging optics, this in turn requiring a pause in the operation of the device, thereby lengthening the average time for the production of a molded body with a fiber-reinforced reinforcing structure. Owing to the pause in operation, unit costs for the molded bodies produced by means of the device and comprising a reinforcing structure are increased. Moreover, the use of imaging optics considerably increases the complexity of a device as per the preamble of the present invention.